Qualities as truthmakers: a quasi-realist account of powers

In this thesis, I set out and defend what I call the Qualities as Truthmakers (QT) Account of Powers. On this novel view, reference to powers is a ‘shorthand’ for a very important truthmaking relation between (i) objects’ qualities, their ways of being, and (ii) what I call ‘maximally specific’ propositions about how those objects either could or would behave in relevant circumstances.

After starting with some ontological preliminaries – including setting out the crucial assumption of basic elements of a neo-Aristotelian substance ontology – I offer an initial characterization of the concept power (to act or to be acted upon), before examining the terms in which the contemporary debate about powers is framed. I argue that both proponents and opponents of powers-based metaphysics err in apparently supposing, with little reflection, that if powers can be truly predicated of things, then those powers must themselves be properties or features of the relevant things. My ‘quasi-realist’ QT Account avoids the realist’s mistake of reifying powers, but still aims to achieve what the realist is after: an explanation of modal truths about objects’ behavior wholly in terms of the genuine properties of those objects, with implications ‘downstream’ in metaphysics and elsewhere for causality, modality, laws of nature, and perhaps much more.

I then marry my QT Account of Powers to the idea that causation – understood as consisting in the production or bringing-about of effects rather than mere ‘difference making’ – is, at root, a matter of specific varieties of causal action, i.e. causings understood as particular types of doings. This leads to what I call the Substances as Producers (SP) Account of Causation – an approach that, I contend, succeeds where other powers-based accounts fail, including by finding a real place for genuine production.